linux/drivers/bus/vexpress-config.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *
   4 * Copyright (C) 2014 ARM Limited
   5 */
   6
   7#include <linux/err.h>
   8#include <linux/init.h>
   9#include <linux/io.h>
  10#include <linux/module.h>
  11#include <linux/of.h>
  12#include <linux/platform_device.h>
  13#include <linux/of_device.h>
  14#include <linux/sched/signal.h>
  15#include <linux/slab.h>
  16#include <linux/vexpress.h>
  17
  18#define SYS_MISC                0x0
  19#define SYS_MISC_MASTERSITE     (1 << 14)
  20
  21#define SYS_PROCID0             0x24
  22#define SYS_PROCID1             0x28
  23#define SYS_HBI_MASK            0xfff
  24#define SYS_PROCIDx_HBI_SHIFT   0
  25
  26#define SYS_CFGDATA             0x40
  27
  28#define SYS_CFGCTRL             0x44
  29#define SYS_CFGCTRL_START       (1 << 31)
  30#define SYS_CFGCTRL_WRITE       (1 << 30)
  31#define SYS_CFGCTRL_DCC(n)      (((n) & 0xf) << 26)
  32#define SYS_CFGCTRL_FUNC(n)     (((n) & 0x3f) << 20)
  33#define SYS_CFGCTRL_SITE(n)     (((n) & 0x3) << 16)
  34#define SYS_CFGCTRL_POSITION(n) (((n) & 0xf) << 12)
  35#define SYS_CFGCTRL_DEVICE(n)   (((n) & 0xfff) << 0)
  36
  37#define SYS_CFGSTAT             0x48
  38#define SYS_CFGSTAT_ERR         (1 << 1)
  39#define SYS_CFGSTAT_COMPLETE    (1 << 0)
  40
  41#define VEXPRESS_SITE_MB                0
  42#define VEXPRESS_SITE_DB1               1
  43#define VEXPRESS_SITE_DB2               2
  44#define VEXPRESS_SITE_MASTER            0xf
  45
  46struct vexpress_syscfg {
  47        struct device *dev;
  48        void __iomem *base;
  49        struct list_head funcs;
  50};
  51
  52struct vexpress_syscfg_func {
  53        struct list_head list;
  54        struct vexpress_syscfg *syscfg;
  55        struct regmap *regmap;
  56        int num_templates;
  57        u32 template[]; /* Keep it last! */
  58};
  59
  60struct vexpress_config_bridge_ops {
  61        struct regmap * (*regmap_init)(struct device *dev, void *context);
  62        void (*regmap_exit)(struct regmap *regmap, void *context);
  63};
  64
  65struct vexpress_config_bridge {
  66        struct vexpress_config_bridge_ops *ops;
  67        void *context;
  68};
  69
  70
  71static DEFINE_MUTEX(vexpress_config_mutex);
  72static u32 vexpress_config_site_master = VEXPRESS_SITE_MASTER;
  73
  74
  75static void vexpress_config_set_master(u32 site)
  76{
  77        vexpress_config_site_master = site;
  78}
  79
  80static void vexpress_config_lock(void *arg)
  81{
  82        mutex_lock(&vexpress_config_mutex);
  83}
  84
  85static void vexpress_config_unlock(void *arg)
  86{
  87        mutex_unlock(&vexpress_config_mutex);
  88}
  89
  90
  91static void vexpress_config_find_prop(struct device_node *node,
  92                const char *name, u32 *val)
  93{
  94        /* Default value */
  95        *val = 0;
  96
  97        of_node_get(node);
  98        while (node) {
  99                if (of_property_read_u32(node, name, val) == 0) {
 100                        of_node_put(node);
 101                        return;
 102                }
 103                node = of_get_next_parent(node);
 104        }
 105}
 106
 107static int vexpress_config_get_topo(struct device_node *node, u32 *site,
 108                u32 *position, u32 *dcc)
 109{
 110        vexpress_config_find_prop(node, "arm,vexpress,site", site);
 111        if (*site == VEXPRESS_SITE_MASTER)
 112                *site = vexpress_config_site_master;
 113        if (WARN_ON(vexpress_config_site_master == VEXPRESS_SITE_MASTER))
 114                return -EINVAL;
 115        vexpress_config_find_prop(node, "arm,vexpress,position", position);
 116        vexpress_config_find_prop(node, "arm,vexpress,dcc", dcc);
 117
 118        return 0;
 119}
 120
 121
 122static void vexpress_config_devres_release(struct device *dev, void *res)
 123{
 124        struct vexpress_config_bridge *bridge = dev_get_drvdata(dev->parent);
 125        struct regmap *regmap = res;
 126
 127        bridge->ops->regmap_exit(regmap, bridge->context);
 128}
 129
 130struct regmap *devm_regmap_init_vexpress_config(struct device *dev)
 131{
 132        struct vexpress_config_bridge *bridge;
 133        struct regmap *regmap;
 134        struct regmap **res;
 135
 136        bridge = dev_get_drvdata(dev->parent);
 137        if (WARN_ON(!bridge))
 138                return ERR_PTR(-EINVAL);
 139
 140        res = devres_alloc(vexpress_config_devres_release, sizeof(*res),
 141                        GFP_KERNEL);
 142        if (!res)
 143                return ERR_PTR(-ENOMEM);
 144
 145        regmap = (bridge->ops->regmap_init)(dev, bridge->context);
 146        if (IS_ERR(regmap)) {
 147                devres_free(res);
 148                return regmap;
 149        }
 150
 151        *res = regmap;
 152        devres_add(dev, res);
 153
 154        return regmap;
 155}
 156EXPORT_SYMBOL_GPL(devm_regmap_init_vexpress_config);
 157
 158static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
 159                int index, bool write, u32 *data)
 160{
 161        struct vexpress_syscfg *syscfg = func->syscfg;
 162        u32 command, status;
 163        int tries;
 164        long timeout;
 165
 166        if (WARN_ON(index >= func->num_templates))
 167                return -EINVAL;
 168
 169        command = readl(syscfg->base + SYS_CFGCTRL);
 170        if (WARN_ON(command & SYS_CFGCTRL_START))
 171                return -EBUSY;
 172
 173        command = func->template[index];
 174        command |= SYS_CFGCTRL_START;
 175        command |= write ? SYS_CFGCTRL_WRITE : 0;
 176
 177        /* Use a canary for reads */
 178        if (!write)
 179                *data = 0xdeadbeef;
 180
 181        dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
 182                        func, command, *data);
 183        writel(*data, syscfg->base + SYS_CFGDATA);
 184        writel(0, syscfg->base + SYS_CFGSTAT);
 185        writel(command, syscfg->base + SYS_CFGCTRL);
 186        mb();
 187
 188        /* The operation can take ages... Go to sleep, 100us initially */
 189        tries = 100;
 190        timeout = 100;
 191        do {
 192                if (!irqs_disabled()) {
 193                        set_current_state(TASK_INTERRUPTIBLE);
 194                        schedule_timeout(usecs_to_jiffies(timeout));
 195                        if (signal_pending(current))
 196                                return -EINTR;
 197                } else {
 198                        udelay(timeout);
 199                }
 200
 201                status = readl(syscfg->base + SYS_CFGSTAT);
 202                if (status & SYS_CFGSTAT_ERR)
 203                        return -EFAULT;
 204
 205                if (timeout > 20)
 206                        timeout -= 20;
 207        } while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
 208        if (WARN_ON_ONCE(!tries))
 209                return -ETIMEDOUT;
 210
 211        if (!write) {
 212                *data = readl(syscfg->base + SYS_CFGDATA);
 213                dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
 214        }
 215
 216        return 0;
 217}
 218
 219static int vexpress_syscfg_read(void *context, unsigned int index,
 220                unsigned int *val)
 221{
 222        struct vexpress_syscfg_func *func = context;
 223
 224        return vexpress_syscfg_exec(func, index, false, val);
 225}
 226
 227static int vexpress_syscfg_write(void *context, unsigned int index,
 228                unsigned int val)
 229{
 230        struct vexpress_syscfg_func *func = context;
 231
 232        return vexpress_syscfg_exec(func, index, true, &val);
 233}
 234
 235static struct regmap_config vexpress_syscfg_regmap_config = {
 236        .lock = vexpress_config_lock,
 237        .unlock = vexpress_config_unlock,
 238        .reg_bits = 32,
 239        .val_bits = 32,
 240        .reg_read = vexpress_syscfg_read,
 241        .reg_write = vexpress_syscfg_write,
 242        .reg_format_endian = REGMAP_ENDIAN_LITTLE,
 243        .val_format_endian = REGMAP_ENDIAN_LITTLE,
 244};
 245
 246
 247static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
 248                void *context)
 249{
 250        int err;
 251        struct vexpress_syscfg *syscfg = context;
 252        struct vexpress_syscfg_func *func;
 253        struct property *prop;
 254        const __be32 *val = NULL;
 255        __be32 energy_quirk[4];
 256        int num;
 257        u32 site, position, dcc;
 258        int i;
 259
 260        err = vexpress_config_get_topo(dev->of_node, &site,
 261                                &position, &dcc);
 262        if (err)
 263                return ERR_PTR(err);
 264
 265        prop = of_find_property(dev->of_node,
 266                        "arm,vexpress-sysreg,func", NULL);
 267        if (!prop)
 268                return ERR_PTR(-EINVAL);
 269
 270        num = prop->length / sizeof(u32) / 2;
 271        val = prop->value;
 272
 273        /*
 274         * "arm,vexpress-energy" function used to be described
 275         * by its first device only, now it requires both
 276         */
 277        if (num == 1 && of_device_is_compatible(dev->of_node,
 278                        "arm,vexpress-energy")) {
 279                num = 2;
 280                energy_quirk[0] = *val;
 281                energy_quirk[2] = *val++;
 282                energy_quirk[1] = *val;
 283                energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
 284                val = energy_quirk;
 285        }
 286
 287        func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
 288        if (!func)
 289                return ERR_PTR(-ENOMEM);
 290
 291        func->syscfg = syscfg;
 292        func->num_templates = num;
 293
 294        for (i = 0; i < num; i++) {
 295                u32 function, device;
 296
 297                function = be32_to_cpup(val++);
 298                device = be32_to_cpup(val++);
 299
 300                dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
 301                                func, site, position, dcc,
 302                                function, device);
 303
 304                func->template[i] = SYS_CFGCTRL_DCC(dcc);
 305                func->template[i] |= SYS_CFGCTRL_SITE(site);
 306                func->template[i] |= SYS_CFGCTRL_POSITION(position);
 307                func->template[i] |= SYS_CFGCTRL_FUNC(function);
 308                func->template[i] |= SYS_CFGCTRL_DEVICE(device);
 309        }
 310
 311        vexpress_syscfg_regmap_config.max_register = num - 1;
 312
 313        func->regmap = regmap_init(dev, NULL, func,
 314                        &vexpress_syscfg_regmap_config);
 315
 316        if (IS_ERR(func->regmap)) {
 317                void *err = func->regmap;
 318
 319                kfree(func);
 320                return err;
 321        }
 322
 323        list_add(&func->list, &syscfg->funcs);
 324
 325        return func->regmap;
 326}
 327
 328static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
 329{
 330        struct vexpress_syscfg *syscfg = context;
 331        struct vexpress_syscfg_func *func, *tmp;
 332
 333        regmap_exit(regmap);
 334
 335        list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
 336                if (func->regmap == regmap) {
 337                        list_del(&syscfg->funcs);
 338                        kfree(func);
 339                        break;
 340                }
 341        }
 342}
 343
 344static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
 345        .regmap_init = vexpress_syscfg_regmap_init,
 346        .regmap_exit = vexpress_syscfg_regmap_exit,
 347};
 348
 349
 350static int vexpress_syscfg_probe(struct platform_device *pdev)
 351{
 352        struct vexpress_syscfg *syscfg;
 353        struct resource *res;
 354        struct vexpress_config_bridge *bridge;
 355        struct device_node *node;
 356        int master;
 357        u32 dt_hbi;
 358
 359        syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
 360        if (!syscfg)
 361                return -ENOMEM;
 362        syscfg->dev = &pdev->dev;
 363        INIT_LIST_HEAD(&syscfg->funcs);
 364
 365        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 366        syscfg->base = devm_ioremap_resource(&pdev->dev, res);
 367        if (IS_ERR(syscfg->base))
 368                return PTR_ERR(syscfg->base);
 369
 370        bridge = devm_kmalloc(&pdev->dev, sizeof(*bridge), GFP_KERNEL);
 371        if (!bridge)
 372                return -ENOMEM;
 373
 374        bridge->ops = &vexpress_syscfg_bridge_ops;
 375        bridge->context = syscfg;
 376
 377        dev_set_drvdata(&pdev->dev, bridge);
 378
 379        master = readl(syscfg->base + SYS_MISC) & SYS_MISC_MASTERSITE ?
 380                        VEXPRESS_SITE_DB2 : VEXPRESS_SITE_DB1;
 381        vexpress_config_set_master(master);
 382
 383        /* Confirm board type against DT property, if available */
 384        if (of_property_read_u32(of_root, "arm,hbi", &dt_hbi) == 0) {
 385                u32 id = readl(syscfg->base + (master == VEXPRESS_SITE_DB1 ?
 386                                 SYS_PROCID0 : SYS_PROCID1));
 387                u32 hbi = (id >> SYS_PROCIDx_HBI_SHIFT) & SYS_HBI_MASK;
 388
 389                if (WARN_ON(dt_hbi != hbi))
 390                        dev_warn(&pdev->dev, "DT HBI (%x) is not matching hardware (%x)!\n",
 391                                        dt_hbi, hbi);
 392        }
 393
 394        for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") {
 395                struct device_node *bridge_np;
 396
 397                bridge_np = of_parse_phandle(node, "arm,vexpress,config-bridge", 0);
 398                if (bridge_np != pdev->dev.parent->of_node)
 399                        continue;
 400
 401                of_platform_populate(node, NULL, NULL, &pdev->dev);
 402        }
 403
 404        return 0;
 405}
 406
 407static const struct platform_device_id vexpress_syscfg_id_table[] = {
 408        { "vexpress-syscfg", },
 409        {},
 410};
 411MODULE_DEVICE_TABLE(platform, vexpress_syscfg_id_table);
 412
 413static struct platform_driver vexpress_syscfg_driver = {
 414        .driver.name = "vexpress-syscfg",
 415        .id_table = vexpress_syscfg_id_table,
 416        .probe = vexpress_syscfg_probe,
 417};
 418module_platform_driver(vexpress_syscfg_driver);
 419MODULE_LICENSE("GPL v2");
 420